THE EGG-EATING SNAKE 



attends the gliding of the snake. The former suggest 

 forcibly that they want practice in the art of walking 

 without limbs. When the snake feeds it engulphs its 

 food in a way totally different to that of the lizard. The 

 two halves of the lower jaw, instead of being bound to- 

 gether by solid bony union, as in the lizards, for the most 

 part, are only connected by softish ligament, and thus 

 can be stretched and allow their possessor to manage a 

 very big morsel. The lizards are compelled to exercise 

 greater moderation in the size of their prey. Were a 

 python a lizard, it would have to be content with rats 

 instead of being able to get outside a goat. A flickering 

 bifid tongue is a character of the snakes, and though it is 

 found in lizards it is not by any means universal in that 

 group. For the rest, snakes have, like lizards, the same 

 alternation between extreme alertness and sluggish 

 laziness. Snakes are entirely animal feeders and devour 

 living prey, with the exception of two egg-eating snakes, 

 of which one, the African Dasypeltis scabra, is often to 

 be seen at the Zoo. Lizards vary their diet more, and 

 they not only eat living prey and eggs, but also are in 

 the case of some species, vegetarians. When we come 

 to internal characters there are more means of distin- 

 guishing between the two orders. The principal one, and 

 it is one that is not usually so much dwelt upon in books 

 contrasting the anatomy of the two groups, is seen in 

 the way in which the internal organs are packed in the 

 body. In all lizards the stomach, intestines, liver, and 

 so forth, lie in a spacious cavity known to anatomists as 

 the ccelom. In snakes the ccelom is still there ; but, 

 instead of forming one large cavity, with plenty of room 

 for more organs than already lie in it, it is divided up 

 into a series of more restricted cavities, in each of which 

 lies some special organ. Thus, the long and narrow 

 liver is enveloped in two sacs meeting in its middle line 

 and showing incidentally that the apparently single- 



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